The present invention relates generally to dishwasher technology and, more particularly, to a method of insulating a dishwasher with an acoustical insulation blanket of thermoplastic material and a dishwasher so insulated.
Automatic dishwashers have long been known as a particularly convenient and efficient way to clean dishes following their use. Such dishwashers generally include a washing chamber for holding the dishes and one or more streams of pressurized fluid for washing food and drink residue from the dishes. Unfortunately, the washing process generates considerable noise, which can be quite annoying to the user. In an effort to reduce this noise it has long been known to provide dishwashers with acoustical insulation.
Conventional acoustical insulation systems for dishwashers generally comprise sound transmission barriers and sound absorption layers. Typically, acoustical insulation involves enclosing the noise source in an insulation structure. A typical form of acoustical insulation is a layer of mineral fiber insulation, such as fiberglass insulation, wrapped around or positioned around the source of unwanted noise. For example, a fiberglass absorber is usually incorporated in the front door panel of an under-the-counter dishwasher. The blanket of glass fibers absorbs some of the sound energy entering the fiberglass board, thereby resulting in a reduced transmission of unwanted sound from the source of the sound in the dishwasher.
While useful for its intended purpose, fiberglass absorbers suffer from a number of shortcomings. Fiberglass material may potentially cause skin irritations when repeatedly handled. In order to address this problem and protect manufacturing employees who repeatedly handle the fiberglass insulation boards, the boards are now encapsulated in a polyethylene or like film. Such an arrangement is disclosed in U.S. Pat. Nos. 4,985,106 and 5,044,705. Although effective for protecting individuals from contact with the fiberglass material, this processing does not allow for exact fit and function when the board is installed on a dishwasher. Specifically, cutout areas such as those provided around water supply and drain lines must be oversized to allow for the encapsulation process. These oversized cutout areas leave gaps between the fiberglass board and the projecting structures that often impair the acoustical performance of the material.
Further, the polyethylene outer film has a tendency to catch on objects. This complicates the packaging of the dishwasher by the manufacturer. Specifically, corner posts and boxes are used to package the finished under-the-counter dishwasher and the exposed polyethylene layer may catch and tear exposing the fiberglass insulation. Of course, the outer polyethylene layer or film may also be torn when installing or removing the dishwasher for repair. As noted above such tears expose bare fiberglass potentially causing irritation to the worker or homeowner. As a further consideration, the resulting poor appearance may also adversely affect customer satisfaction with the dishwasher.
Still further, it should be appreciated that the fiberglass board cannot be contour molded. Accordingly, the thickness of the fiberglass used is determined by the minimum clearance point between the outer casing of the dishwasher and the under counter opening for which the dishwasher is designed.
From a review of the above it should be appreciated that a need exists for a dishwasher having improved acoustical insulation as well as for a method of acoustically insulating a dishwasher.
To achieve the foregoing and other objects and in accordance with the purposes of the present invention as described herein, an improved dishwasher is provided. That dishwasher includes a housing having a washing chamber and a door for gaining access to the washing chamber. A washing nozzle is provided in the washing chamber. The nozzle functions to direct a fluid stream against dishes held in the washing chamber. A circulation pump circulates fluid under pressure through the washing nozzle. The dishwasher also includes a supply line for delivering fluid to the circulation pump and a drain line for discharging fluid from the washing chamber.
Still further, the dishwasher includes an acoustical insulation blanket of thermoplastic material. The acoustical insulation blanket extends around the washing chamber and the circulation pump and is precisely cut to fit snugly around the fluid supply line and the drain line so as to eliminate gaps therebetween and the acoustical leaks associated therewith.
The thermoplastic material utilized for the acoustical insulation blanket is selected from a group of fibers consisting of polyester, polyolefin, polyethylene, rayon, nylon, acrylic, hemp, kenaf, cotton and combinations thereof. The acoustical insulation blanket may be composed of polyester staple fibers and polyester bicomponent fibers of distinct diameters typically between 8.0 and 50.0 microns and distinct lengths typically between 0.5 and 3.0 inches. The acoustical insulation blanket may also include melt blown microfibers.
Still further the acoustical insulation blanket may include a facing layer such as a scrim in order to protect the material during handling of the dishwasher. Alternatively or in addition, the acoustical insulation blanket may include a relatively high-density skin on at least one face thereof for the same purpose.
In accordance with yet another aspect of the present invention, a method is provided for insulating a dishwasher. The method comprises the step of enclosing the noise generating components of the dishwasher in an acoustical insulation blanket of thermoplastic material.
Still further, the method may include the step of precisely cutting the acoustical insulation blanket to fit snugly around selected projecting structures so as to eliminate gaps between the blanket and the structures and, therefore, acoustical leaks associated with those gaps.
Still further, the method may include the step of contour molding the acoustical insulation blanket to a desired shape. Further, the method includes the crimping of the acoustical insulation blanket in selected areas. Together, the contour molding and crimping allow a custom fit for any particular application and thereby ensure that acoustical insulating efficiencies of the material are maximized.
Still other objects of the present invention will become readily apparent to those skilled in this art from the following description wherein there is shown and described several embodiments of this invention simply by way of illustration of some of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modification in various, obvious aspects all that departing from the invention. Accordingly, the drawing and descriptions will be regarded as illustrative in nature and not as restrictive.